April 13 project update: Bertha's next move

Posted on Apr 13 2017 4:54 PM

Seattle Tunnel Partners began moving Bertha, the SR 99 tunneling machine, into the disassembly pit this morning. Crews began pushing the machine forward at approximately 9 a.m. this morning and have completed building ring 1,419.

In the coming weeks, the machine will move forward approximately 80 feet before coming to rest in its final position. Along the way it will build the final rings of the tunnel, as well as a short section of temporary partial rings that the machine will use to push itself forward in the pit.

Once the machine is in place, crews will begin cutting the machine into pieces and removing them from the pit. Some parts may be salvaged for use on other projects, while other parts will be recycled.

Brace removal

Crews spent the past several days cleaning the pit and removing the braces from the wall Bertha bored through on April 4. The time-lapse video below shows crews removing the braces.